NBME - 24 2023 with verified questions and answers

tetrodotoxin inhibits which ion channel - what is the result of this? sodium channels - causes cardiac arrest this toxin is found in puffer fish dark urine in the mornings - what is the pathogenesis of this condition? this condition is paroxysmal nocturnal hemoglobinuria = defect in PIGA / cell membrane anchoring protein -- decreased expression of Decay accelerating factor and membrane inhibitor of reactive lysis synaptobrevin is found where? what is its function? on the vesicles - helps with vesicle fusion what is the function of SNARE proteins? what are they inhibited by? help with vesicle fusion / neurotransmitter release inhibited by tetanus toxin (inhibits renshaw release of GABA and Glycine) also inhibited by botulinum toxin (inhibits ACh release) MOA of tetanus toxin - which toxin is this similar to Cleaves SNARE proteins and inhibits neurotransmitter (GABA / Glycine release) - similar to botulinum toxin after blood flow is returned to an area which substance causes hyperemia adenosine what substances vascular dilation in skeletal muscle CO2, H+, Adenosine, lactate, K+ (CHALK) hypoketotic hypoglycemia in an infant - what is this due to defect in beta oxidation - most commonly due to MCAD deficiency (medium chain acyl dehydrogenase deficiency) what type of viruses are killed by being dried or acidified enveloped viruses (such as coronaviruses) what are two common causes of the "common cold" Rhinovirus, coronavirus which viruse(s) are associated with reactive CD8+ lymphocytes CMV and EBV (EBV would have positive monospot / heterophile agglutination with sheep or horse blood) what is a complication of pneumothorax respiratory acidosis what are schwan cells derived from? neural crest effect of being supine for a long time on volume status eventual decrease in volume status due to increased venous return from being supine -- increased cardiac output -- pressure natriuresis bone marrow increases what in response to blood loss d-ALA / 5 aminolevulinic acid where in the body does heme synthesis occur? bone marrow what is the inheritance of schizophrenia? multifactorial - similar to diabetes Type I inheritance lamins are found where? nuclear envelope - fibrous proteins that contribute to the 2D network on the inner surface of the nuclear membrane most common causes of adrenal insufficiency in the developed vs. not developed world in developed world = autoimmune adrenalitis not developed = TB what causes cell swelling during periods of ischemia decreased ATP -- defective Na / K ATPase -- accumulation of calcium and sodium inside the cell -- attracts free water -- swelling crystal content of gout vs. pseudogout gout = uric acid / monosodium urate pseudogout = calcium pyrophosphate streak ovaries are associated with turner syndrome boobs no pubes is due to ? what lab value will be different? androgen insensitivity - elevated testosterone klinefelter presentation gynecomastia, small firm testes, man who is having trouble with fertility, psychosocial abnormalities what is the role of Transporter associated with antigen processing (TAP) what will deficiency of this result in? it brings cytosolic proteins to MHCI if TAP is deficient you lose MHCI expression -- bare lymphocyte syndrome is metaplasia reverisble or irreversible? REVERSIBLE upper versus lower motor neuron signs lower motor neuron signs = flacid paralysis, fasiculations & atrophy upper = hyperreflexia, babinskisi, and spastic paralysis which phase are the mitotic cyclins synthesized in G2 phase side effects of NRTI's such as zidovudine agranulocytosis, hepatotoxicity, lactic acidosis presentation of vitamin E deficiency looks like B12 deficiency - subacute combined degeneration -- hyporeflexia but is normocytic and no MMA increase also has hemolytic anemia whereas B12 deficiency does NOT what is the scientific name for head louse pediculus humanis capitis osmotic and volume status of hyperglycemia hyperosmolar hyponatremic --- intracellular and extracellular dehydration (even if the patient has not voided) increased vascular permeability increases hydrostatic pressure where? what is the effect of this? increases interstitial hydrostatic pressure -- increased flow into the lymphatics a patient being treated for rheumatoid arthritis with new onset back pain and night sweats - what is the cause TNF alpha inhibitor treatment -- reactivation of TB -- pott's disease (TB in the lumbar region of the spine causing abscess/ osteomyelitis - pathology shows granuloma formation with negative gram stain) What are the TNF alpha inhibitors what is their major concerning side effect? adalimumab, etanercept, infliximab -- reactivation of latent TB/ pott's disease what test should you perform before perscribing TNFa inhibitors PPD embryology of spina bifida - failure of what? failure of fusion of somite sclerotomes pathophysiology of allodynia persistent activation of voltage gated sodium channels on the nociceptor how does POMC generate opioids melanin and cortisol cleavage of the precursor protein AKA post translational modification palpable right ventricular lift pulmonary stenosis MOA of HMG CoA Reductase inhibitors increased LDL receptor expression on cell surface (decreased degradation / increased recycling) decrease LDL production via decreased cholesterol synthesis (HMG CoA Reductase is rate limiting enzyme for cholesterol synthesis) TRALI vs. TACO pathophysiology TACO - similar to acute left sided heart failure TRALI - due to donor antibodies against host neutrophils -- activation / destruction of neutrophils -- vascular permeability in the lungs (pathophys somewhat similar to septic shock - no increased PCWP) - hypotension, fever, transient leukopenia - neutrophil mediated damage to the lung vasculature where does the thyroid originate? in the foramen cecum of the tongue and then descends hydrocephalus after repair of berry aneurysm is due to decreased uptake by arachnoid granulations the same mechanism of hydrocephalus can occur following meningitis IMA drains into the splenic vein the portal vein is formed from Splenic + SMV superior rectal vein drains into where? inferior mesenteric vein which drains into the splenic, which then combines with the superior mesenteric vein to form the portal vein body louse is associated with which pathogens? bartonella -- culture negative endocarditis and trench fever ixodes tick is associated with which pathogens? lyme disease / borrelia burgdorferi babesia black fly is associated with which pathogen onchocerca Coulex mosquito is associated with which pathogen arbovirus infections such as West Nile virus, Japanese encephalitis, or St. Louis encephalitis, but also filariasis and avian malaria which pathogen is associated with anopheles mosquito malaria which pathogen is associated with aedes mosquito zika reduvidd / kissing bug is associated with which pathogen(s) Trypanosomes - brucei = sleeping sickness cruzi = dilated cardiomyopathy and achalasia which is deeper in the skin, hemidesmosomes or desmosomes hemidesmosomes are deeper - they connect the basal keratinocytes to the basement membrane bullous pemphigoid pathogenesis autoimmune destruction of hemidesmosomes pemphigus vulgaris pathogenesis autoimmune destruction of desmosomes / desmoglein anion gap calculation Na - (Cl + HCO3) what is a common cause of normal anion gap metabolic acidosis renal tubular acidosis what does a sertoli leydig tumor produce testosterone shuffner stippling is associated with which pathogens? P vivax and P ovale which pathogens produce hypnozoites P vivax and P ovale pain after eating in a patient with evidence of atherosclerosis is due to what? chronic mesenteric ischemia affecting the SMA and IMA trichinella spiralis presentation myaliga and fever in hunters who eat wild meat presentation of pineal gland tumor parinaud syndrome - sunsight sign compression of vertical gaze center - RIMLF (rostral interstitial nucleus of the medial longitudinal fasiculus) presentation of dorsal root ganglion damage impaired sensation and hyporeflexia due to interrupting circuit involved in reflexes conjugation vs. transduction vs. transposition microbiology ... HNPCC is due to defect in which gene MSH2 = mismatch repair gene